Structural similarity between the prion domain of HET-s and a homologue can explain amyloid cross-seeding in spite of limited sequence identity.

We describe a distant homologue of the fungal HET-s prion, which is found in the fungus Fusarium graminearum. The domain FgHET-s(218-289), which corresponds to the prion domain in HET-s from Podospora anserina, forms amyloid fibrils in vitro and is able to efficiently cross-seed HET-s(218-289) prion formation. We structurally characterize FgHET-s(218-289), which displays 38% sequence identity with HET-s(218-289).

New insights into structure-function relationships of oxalyl CoA decarboxylase from Escherichia coli.

The gene yfdU from Escherichia coli encodes a putative oxalyl coenzyme A decarboxylase, a thiamine diphosphate-dependent enzyme that is potentially involved in the degradation of oxalate. The enzyme has been purified to homogeneity. The kinetic constants for conversion of the substrate oxalyl coenzyme A by the enzyme in the absence and presence of the inhibitor coenzyme A, as well as in the absence and presence of the activator adenosine 5'-diphosphate, were determined using a novel continuous optical assay.